1. Field of the Invention
The present invention relates to a slider-position detector for detecting the position of the slider of a disk player.
2. Description of the Prior Art
In a disk player for playing an information recording disk (hereinafter referred to simply as "disk") such as a video disk, a digital audio disk, etc., a slider carrying a pickup is linearly moved in the radial direction of a disk. The slider is driven by a rotary motor through a mechanical transmission. A rack-and-pinion mechanism, for example, reduces the speed of the rotary motion of the rotary motor and converts the rotary motion into a linear motion to drive the slider for a linear motion.
The speed of the searching operation of the slider with the pickup, namely, an operation for searching a disk for a desired recording track while moving the slider at a high speed, is restricted since the response speeds of the mechanical transmission and the rotary motor are limited. Nevertheless, increase in the speed of the searching operation has been strongly desired in the industry. The speed of the searching operation of the slider may be increased by using a linear motor which has excellent response characteristics, instead of a rotary motor, as a driving source for driving the slider for a linear motion.
Incidentally, the position of the slider in the disk player must be detected to find the position of the pickup relative to the disk. Conventional means for detecting the position of the slider comprises a plurality of mechanical switches disposed in a row near the path of the slider at positions corresponding to the positions of the slider to be detected. The position of the slider is detected by the mechanical switches with which the slider comes into contact.
However, the use of the plurality of mechanical switches increases the manufacturing cost of the disk player. Particularly, the plurality of mechanical switches increase the load on the slider in the employment of a linear motor as a driving source for driving the slider. The use of the mechanical switches is unwanted.